If this is the Islander 34 with the short bow sprit,
then that is a very old design which was just a
reworking of the Islander 32 hull from 1963, with
a different deck and a longer 'J' to try to balance
the weather helm. The same hull was also built
as an I 33 with a different deck. They did a lot
of recycling of models in the early fiberglass boat
building era.
I would expect the Pearson to be the better sailing
boat of the two , especially upwind. But there are
many boats in this size and price range on the market
so you may want to search further.